1. Field of the Invention
This invention relates to new and improved apparatus for attaching insulation to duct work and more particularly to improved hammers and anvils for resistance stud welders and improved retaining pins used in such apparatus.
2. Brief Description of the Prior Art
Hogg et al U.S. Pat. No. 2,110,832 discloses a stud welding apparatus with a special tool for holding a resistance welding pin for attaching insulation to duct work wherein a hammer drives the pin and washer through the insulation to contact metal duct work supported on an anvil and the hammer and anvil comprise the electrodes of the stud welding apparatus.
Nelson U.S. Pat. No. 2,378,720 discloses a chuck for holding the head of a resistance welding pin for use in a stud welding apparatus.
Hinden U.S. Pat. No. 3,591,762 discloses a stud welding apparatus for driving a resistance welding pin for attaching insulation to duct work wherein a hammer drives the pin and washer through the insulation to contact metal duct work supported on an anvil and the hammer and anvil comprise the electrodes of the stud welding apparatus.
Hinden U.S. Pat. No. 3,835,285 discloses an automatic stud welding apparatus for driving a resistance welding pin for attaching insulation to duct work wherein a hammer drives the pin and washer through the insulation to contact metal duct work supported on an anvil and the hammer and anvil comprise the electrodes of the stud welding apparatus.
Hinden U.S. Pat. No. 3,858,024 discloses a multiple head stud welding apparatus for driving a resistance welding pin for attaching insulation to duct work wherein a hammer drives the pin and washer through the insulation to contact metal duct work supported on an anvil and the hammer and anvil comprise the electrodes of the stud welding apparatus.
Hinden U.S. Pat. No. 3,582,603 discloses a method and apparatus for attaching insulation to duct work utilizing a special retaining pin and washer in a stud welding apparatus wherein a hammer drives the pin and washer through the insulation to contact metal duct work supported on an anvil where the hammer and anvil comprise the electrodes of a stud welding apparatus.
Hinden U.S. Pat. No. 4,031,350 discloses a special resistance welding pin and method and apparatus for attaching insulation to duct work utilizing a special retaining pin and washer in a stud welding apparatus wherein a hammer drives the pin and washer through the insulation to contact metal duct work supported on an anvil where the hammer and anvil comprise the electrodes of a stud welding apparatus.
Hinden U.S. Pat. No. 4,429,209 discloses another special resistance welding pin, having a corrugated shank, and method and apparatus for attaching insulation to duct work utilizing a special retaining pin and washer in a stud welding apparatus wherein a hammer drives the pin and washer through the insulation to contact metal duct work supported on an anvil where the hammer and anvil comprise the electrodes of a stud welding apparatus.
Hinden U.S. Pat. No. 4,482,795 discloses another special resistance welding pin, having axially extending heat radiating ribs, and method and apparatus for attaching insulation to duct work utilizing a special retaining pin and washer in a stud welding apparatus wherein a hammer drives the pin and washer through the insulation to contact metal duct work supported on an anvil where the hammer and anvil comprise the electrodes of a stud welding apparatus.
Hinden U.S. Pat. No. 3,701,878 discloses another special resistance welding pin, having a flat shank folded from the same material as the head or washer portion, and method and apparatus for attaching insulation to duct work utilizing a special retaining pin and washer in a stud welding apparatus wherein a hammer drives the pin and washer through the insulation to contact metal duct work supported on an anvil where the hammer and anvil comprise the electrodes of a stud welding apparatus.
Hinden U.S. Pat. No. 3,624,340 discloses a special resistance welding pin, and method and apparatus for attaching insulation to duct work utilizing a special retaining pin and washer in a stud welding apparatus wherein a hammer drives the pin and washer through the insulation to contact metal duct work supported on an anvil where the hammer and anvil comprise the electrodes of a stud welding apparatus.